The present invention relates to a method of texturing a mold surface to provide a desired pattern on a molded article.
In the past, molded plastic articles have been provided with a variety of surface textures by treating the mold in which the articles are formed. In addition, in the manufacture of molded articles, texturing of the surface of a resulting product has often been accomplished by treating the surface of the article after it has been molded such as by chemical etching, mechanical deformation or the like. While the foregoing procedures have been useful for a number of types of molded articles, where the molded article is employed in a building construction as a wall surface, conventional texturing techniques have been difficult to employ particularly where pigments have been included in the mold composition and where the mold composition includes a substantial quantity of a polymerizable resin such as polyester or an epoxy resin. In the mass production of discrete articles wherein each article is provided with a molded surface, it is impractical as a manufacturing expedient to individually treat an article once it has been molded as this appreciably affects the manufacturing cost. In addition, individual handling of articles after they have been molded can all too easily result in non-uniformities in the product as a consequence of the processing steps required subsequent to curing of the article in the mold.
Accordingly, it is an object of the present invention to provide a method of preparing a mold surface so that, in the course of molding an article, the mold will form a pattern on the molded article surface at the same time the article is being formed and cured in the mold.
In summary, the present invention utilizes a mild steel mold element which is first masked to cover a selected surface so that the mold's surface will impress a desired pattern on the molded article. The mold's surface, with the masking material affixed thereto, is then textured as by sandblasting on the uncovered mold surface areas. The mask is then removed and the mold cleaned preparatory to plating the entire mold surface with a metal such as nickel. The plated mold surface is then employed to form a molded article with a plastic resin material such as a polyester resin composition or an epoxy resin composition which may, if desired, incorporate a pigment and a filler such as sand. In a preferred embodiment, the plastic material in flowable form is deposited in the mold and a support member such as, for example, a masonry unit, bracket, wire mesh or the like is placed on the plastic composition so that when the plastic composition is cured in an oven, the composition will harden and be bonded to the surface of the support member. The portion of the composition facing the mold surface will then take on the texture as defined by the masking material so that in the finished article, the exterior surface thereof will take on the desired pattern.
With the method of the present invention, it has been found that the resulting product gives a unique appearance to the molded surface. In particular, the pattern has been observed to vary as an observer moves past the surface and as the angle of incidence of lighting to which the surface is exposed is varied.
The foregoing and other advantages will become apparent as consideration is given to the following description taken in conjunction with the accompanying drawings, in which: